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Soil samples were generally collected using a modified Califorrua split spoon sampler fitted <br /> with stainless steel Liners The sampler was driven Into the soil in front of the drill bit to <br /> collect reasonably undisturbed samples Sample collection from boring B-10 involved driving <br /> a sleeve Into soil accumulated within the hand auger bucket In all borings, two samples from <br />' each interval were retained, one for laboratory analysts and one for soil description and on-site <br /> screening <br />' <br /> Preparation of samples for laboratory analysis Involved first covering both ends of the filled <br /> sleeve with aluminum foil, and then sealing the sleeves with plastic caps The samples were <br /> then appropriately labelled and placed in a cooler on blue ice pending shipment to the <br /> laboratory Sample Identification numbers were recorded on Chain-of- Custody forms <br /> 3 4 2 Field Monitoring for-Volatile Organic Compounds <br /> 1 <br /> One discrete sample was collected at each Interval for on-site field screening for volatile <br />' organic compounds The field monitoring of the samples was conducted using a Microtip <br /> photolonization detector (PID) Prior to field use, the PID was calibrated and bench-tested <br /> Field screening of the soil samples was conducted according to the following procedure <br />! - The soil sample was covered with aluminum foil, capped at one end and then <br /> emptied of half its contents to provide headspace After removing half the <br />' sleeve's contents, the opening was covered with aluminum foil to seal the <br /> vapors from escaping <br />' - The stainless steel sleeves were thenlaced in the sun to allow the sample to <br /> P P <br /> heat and volatilize contaminants in the soil <br /> Once the sample had been allow to heat, the PTD probe tip was inserted Into the <br />' headspace through the aluminum foil to collect the field measurement <br />' As indicated in the boring logs, organic vapors were measured at concentrations up to 126 <br /> ppm The highest PID measurements (> 100 ppm) were recorded in borings B-4 and B-8 <br /> TETRA TECH Stockton Developmental Center,Phase II Site Investigation Report Page IO <br />